1895. | NEW YORK ACADEMY OF SCIENCES. 19 
Contains only finely comminuted fragments of :— 
Asaphus platycephalus. Plectorthis equivalvis. 
Rafinesquina alternata. 
20. Gray agglomeration of Orthis testudinaria, with 
black nodules, but no other fossils - 2297 
21. Zone of fafinesquina deltoidea. Gray finely 
crystalline limestone with mostly regular cleavage, but 
impure and slightly nodular in portions, with shaly 
partings, containing numerous well preserved fossils, 
notably &. deltoidea. Occurs at top of Mill Dam (4th) 
Fall. 235/ 
Rafinesquina deltoidea a a a. Asaphus platyeephalus. 
Orthis ( Platystrophia) biforata c. Ceraurus pleurexanthemus. 
( Dalmanella) testudinaria c¢. Crania Trentonensis. 
Zygospira recurvirostra. Lingula. 
Crinoid columns. 
22. Recurrent shaly layers interbedded with hard, 
compact to crystalline. blue-black layers, 2 to 10 inches 
thick, mostly impure and readily weathering. Several 
conspicuous seams at top. Divided by a seam in the 
middle into two distinct sets of beds. Forms the 
whole cliff beneath the gray beds to the top of Mill Dam 
Fall. Approximately 305/ 
Rafinesquina deltoidea a a. Platistrophia biforata. 
——— alternata a. Calymene senaria. 
23. ‘Trenton Gray Limestone,’ quarried in the 
Prospect Quarries on both banks of the creek at the top 
of the gorge, and shown at the top of the cliff down the 
gorge to the railroad bridge, as illustrated in Plate V. 
Heavy bedded, light-gray coarsely crystalline encrinal 
limestone, very pure and composed of comminuted 
fragments in which few species can be recognized,+ 
with even shaly partings. 325/ 
* Tn the neighboring fields the upper surface of these beds is seen to weather darker, 
and duller hued and has been dissolved into deep crevasses. The stone from F. T. 
Thomas’ quarry, which is considerably used for building contains CaCo, 94.82 per cent. 
and Mg Co, 1.66 per cent. (J. C. Smock, Bull. N. Y. State Museum IT., 246, 1890.) Van- 
uxem says that this ‘‘gray limestone commences at Nine Mile Creek, below Stittville, 
and extends north to near Boonville,’ and is so fissured at Holland Patent that Cincin- 
nati Creek becomes lost init. (Second An. Report on Third District, 1838, p. 276.) And 
again, in his 1842 report already cited, p. 51: ‘‘ Where the road which leads to Prospect 
leaves the one from Trenton Village to Boonville, the water of Cincinnati Creek, above 
the bridge, is seen entering the creek. Higher up, the whole stream is deserted, pre- 
senting a rock surface, under which, and by joints of the rock, the water courses by its 
subterranean route to where it reappears near the bridge.’’ The fossil fragments es- 
specially bryvozoa, weather out on the surface in the fields near Prospect. The lower 
layers are somewhat lighter gray. 
+The beds of gray crystalline limestone with their thin shaly partings closely re- 
semble the Trenton as it occurs at the Mile End Quarries, near Montreal, Canada. The 
latter contains similar fossils, but is slightly bituminous. 
